This invention relates generally to cyclones and particularly but not exclusively to cylones in suction cleaners which draw in air carrying dirt-laden liquid.
Such suction cleaners are described in U.S. Pat. No. 3,262,146 and United Kingdom Patents GB-A-1 448 434, GB-A-1 497 709, and GB-B-2 154 431. In suction cleaners of this type, an upwardly open receptacle for dirt-laden liquid (e.g. water) is provided in a housing whose interior is at a reduced pressure in operation. The volume ratio of air to liquid on entry into the housing may typically be roughly 30 parts of air to one part of liquid. The liquid is therefore in the form of small droplets scattered in the air stream and suspended by the motion and turbulence of the air.
A problem with suction cleaners of this type is that fine droplets remain suspended in the air as it travels through the machine. Although most of them are deposited on surfaces and fall into the collection tank, a significant proportion continues suspended in the air stream and leaves via the suction fan. The soiled liquid droplets then evaporate, leaving a fine dust possibly contaminated with allergens and pathogens suspended in the air. The suspended liquid may eventually damage the mechanism or electrical parts of the suction cleaner. It may also shorten the life of any outlet filters used. There is also the possibility that dirt entrained in the incoming air is not captured by the liquid droplets.
The present invention provides a cyclone in which liquid carried by an incoming stream of air accumulates and circulates while coming repeatedly into contact with the incoming stream.
In particular, the invention provides a cyclone in which solid and liquid particles carried by an incoming stream of air are separated from the air stream, the cyclone having a curvilinear peripheral wall, a top wall extending inwards from the entire periphery of the peripheral wall, and a bottom wall extending substantially horizontally inwards from the entire periphery of the peripheral wall, at least one of the top and bottom walls having an outlet spaced from the peripheral wall, the peripheral wall having an inlet port for the incoming stream of air carrying solid and liquid particles, the inlet port directing the incoming stream substantially tangentially to the peripheral wall so that solid and liquid particles carried by the incoming stream are deposited on the peripheral wall, accumulate on the substantially horizontal bottom wall, and circulate as a body of solid-laden liquid while coming repeatedly into contact with the incoming stream, excess solid-laden liquid escaping through the outlet.
As applied to a suction cleaner, the invention provides a suction cleaner comprising a housing whose interior is at reduced pressure in operation, an upwardly open liquid receptacle in the housing, and a cyclone above the receptacle in the housing, the cyclone having a curvilinear peripheral wall, a top wall extending inwards from the entire periphery of the peripheral wall, and a bottom wall extending substantially horizontally inwards from the entire periphery of the peripheral wall and having an outlet spaced from the peripheral wall and communicating with the receptacle, and the peripheral wall having an inlet port for an incoming stream of air carrying dirt and liquid, the inlet port communicating with the exterior of the housing and directing the incoming stream substantially tangentially to the peripheral wall so that liquid carried by the incoming stream is deposited on the peripheral wall, accumulates on the substantially horizontal bottom wall in the cyclone, and circulates as a body of dirt-laden liquid while coming repeatedly into contact with the incoming stream, excess dirt-laden liquid escaping through the outlet to the receptacle.
Dirt (such as dust, lint, soil, mites, and other debris) carried by the incoming stream of air is captured by the circulating body of dirtladen liquid in the cyclone.
Preferred and optional features are set forth in the claims.